Fade duration and fade slope statistics derived from long-term Anik-F2 satellite beacon measurements in Ottawa-Canada

Abstract

Fade duration and fade slope statistics are used to describe the dynamic behavior of attenuation experienced by terrestrial and satellite radio links. They provide essential information for the design of fade mitigation techniques such as up-link power control, adaptive coding and modulation, and data throughput reduction. Duration and slope statistics covering the 4-year period 2006–2009 have been calculated using propagation data collected at the Communications Research Centre (CRC) in Ottawa from the 20-GHz beacon signal of Telesat's Anik-F2 satellite. The duration distributions have been used to test the performance of several prediction models, including one recommended by the ITU-R and one developed at CRC, and to investigate possible model refinements. The conditional probability density function (PDF) of fade slope shows general symmetry between positive and negative slope values. Models based on symmetric distributions have been proposed in the literature. The cumulative distribution function (CDF) of the absolute value of fade slope reflects the dependence of the rate of change on fade level. Slope CDFs are used to test the ITU-R prediction model. Finally, the comparison of long-term slope statistics derived from the 20- and 30-GHz ACTS satellite beacon signals collected at CRC confirms the frequency-independent behaviour of fade slope in this band.